Basics of Alkali Refining & Water Washing of Vegetable Oils ( Andrew Logan )
Purpose of Alkali Refining
• Removing of impurities from oil
– Phospholipids (gums)
– Colour bodies
– Metal Ions – Pro-oxidants
• Iron
• Copper
– Free Fatty Acids
– Solids – meal fines
Oil Impurities
• Phospholipids
– cause emulsions
– darken oil with heat
– interfere with crystallization
• Colour Bodies
– Some have nutritional value
– Remove to add consumer appeal & functionality in industrial uses
(not heat stable)
• Metal Ions
– act as pro-oxidants degrading the oil quality & stability
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